Calculate the savings first

You might think that demolishing
concrete is backbreaking,
brainless work.
But that’s only half
true. There’s more to it than
just swinging a sledgehammer.
And a bit of know-how can save
you lots of time and sweat and possibly
a visit to the chiropractor’s office.

Tearing up concrete yourself can also save
you a ton of money. Hiring a contractor
just to demolish a 12 x 14-ft. patio
could cost you $1,400 or more. If you
do it yourself, it’ll cost you only
about $400, including rental and disposal.
That’s a savings of about
$1,000. On the other hand, if you’re
hiring a contractor to pour new concrete,
doing the demo yourself could
actually cost you more once you pay disposal costs. Compare the costs of removing it yourself with what the contractor would charge for removal.

Choose your weapon—sledge or jackhammer

Photo 1: 12-lb. sledge

A sledge can be surprisingly effective in breaking up concrete up to about 4-in. thick. Give it a try first, before moving on to heavier rental equipment.

Photo 2: The jackhammer option

A rented jackhammer powered by a
big compressor is the best option for
large or thick slabs. But a plain old
sledgehammer is fine for most jobs.

The surest way to decide whether
to use a sledgehammer or a jackhammer
is to experiment a few
days before you begin full-scale
demolition. Just take a few whacks
at the slab with a sledgehammer (Photo 1).
Within 10 minutes, you’ll know
whether it’s a job for a sledge or a
jackhammer. Consider renting an
electric jackhammer
to make the job easier. It won’t save
you much time, but it’s a lot easier
on your body.

If your slab is large or extra
thick, rent a pneumatic jackhammer
(with a hose, bits and a trailer-mounted
compressor; Photo 2). It has much more
power than an electric jackhammer.
But it’s also heavy (90 lbs.)
and difficult to maneuver. Don’t
automatically assume you should
rent this as your first choice—it’s
overkill for most home concrete
breakup projects.

Plan your disposal strategy

Trash container with gate

Rent a trash container with a gate so you can dump your wheelbarrow inside.
Tossing chunks over the side is hard work.

Concrete can’t go in your trash can,
so check out your disposal options at
least a week ahead. Some concrete
recyclers (search online for “recycling services”) accept it
free or charge a small fee per load.
Most add an extra charge if the concrete
contains steel mesh or rebar.
Unfortunately, you won’t know if
yours has metal in it until you start
breaking it apart. So figure your total
price based on the higher rate. Also
be aware that the typical 12 x 14-ft.
patio weighs about 5,000 lbs. That
means you’ll be paying the charges
for at least three loads and making at
least three trips, even if you have a
1-ton pickup truck.

Your other option is to rent a trash
container (check the yellow pages
under “waste disposal”). Don’t guess
on the proper size. Instead, give the
waste haulers the dimensions and
thickness of your patio and let them
figure out the right size for your job.
Make sure any trash container you rent has a walk-in gate for easier loading.

Round up a crew

This is one project where it really pays to have extra
bodies around to do the heavy lifting. So plan ahead
and nail down firm commitments from friends who
owe you favors. Friends who own heavy-duty wheelbarrows
are especially valuable. Ideally, your crew will
consist of two to break up the concrete and a team of
two to four to haul the rubble away.

Stop flying shrapnel

Cover the slab

Stop flying chunks of concrete with a sheet of plastic. Concrete
shrapnel can damage siding and break windows, and it's a real
chore to clean up.

Flying shards of concrete can damage siding, break glass
or even cut you. Rather than setting up plywood to protect
windows and siding, roll 6-mil polyethylene (at
home centers) over the patio or sidewalk. Leave it in place
while you hammer or jackhammer. The sheeting catches
all the shrapnel and traps most of the dust. Just be sure
to watch your step while walking on it—poly can be very
slippery.

Don't just hammer—pry, too

Photo 1: Pry and break

Break up concrete faster by forming a two-person team. With
one person prying up while the other strikes, concrete breaks
more easily.

Photo 2: Pry bar

Use a 5 to 6-ft. long chisel-tip pry bar to lift concrete edges.

After you’ve covered the slab with plastic, it’s
tempting to just start whaling away. Don’t! The sand base
under the slab will absorb the energy from each blow.
You’ll end up exhausted with very little to show for
it. Worse, you’ll pulverize the top layer of the
slab instead of creating deep cracks.

The key to a quick job is a two-person
team: one with a sledge or jackhammer;
the other with a 5- to 6-ft.-long
pry bar, sometimes called a “San Angelo bar” (available
at some rental centers or at home centers; Photo 2).
Start at the corners and work inward. If the concrete
doesn’t crack with the first blow, aim your next hit a
few inches away. Never strike the same spot twice. That
just chips the surface, creating a cushion of fine rubble
over the slab, and makes it harder to break.

Jackhammer tips

Photo 1: Jackhammer technique

Take small bites with a jackhammer to crack the concrete.
If you begin to drill a hole without creating a crack, STOP!
Otherwise, you’ll get the bit stuck in the concrete.

Photo 2: Chisel-point bit

Use the chisel-point bit for faster results.

Rental jackhammers come with an assortment of
bits, but only use the chisel-point bit (Photo 2). The point
concentrates the jackhammer’s force and cracks
the concrete faster than the wider bits can.
Here’s an important jackhammer warning: If
you try to crack off large pieces, the jackhammer
will literally drill itself into the concrete
and get stuck. You’ll spend more time
getting it unstuck than it takes to crack
more but smaller pieces. So move the
bit no more than 2 to 3 in. back from
the nearest crack before you hit the
trigger. As with a sledgehammer,
breakup is faster and easier if
you have a helper pry up with
a long bar as you work.

Separate the chunks

Pry out concrete chunks

Loosen locked-together chunks of concrete. A mattock is the
perfect tool for prying them apart or pulling them up.

Even after concrete is broken, the chunks remain locked
together, making the surrounding concrete harder to
break. So clear away the rubble after you've broken up
each 2- to 3-ft. section. Don’t use your hands to pry out
the sections—a mattock is the best tool for this job.
To separate the chunks, swing the pointed end of the
mattock into the crack and pry up. Push the pieces far
enough apart so you can switch to the larger flat blade.
If the chunk won’t budge, move the mattock to the
opposite side of the chunk above the flat edge under the
concrete. Then lift up to "unlock" the stuck edge.

Dealing with mesh or rebar

Snip reinforcement wire

Snip through wire mesh to separate chunks of concrete. Bolt
cutters are the best tool for this job; don't even try using a
wire cutter.

Many slabs contain reinforcing steel mesh to resist
cracking. That can double or even triple the time it takes
to tear out the slab. If you try to break off large pieces,
the reinforcing mesh will do its job and resist cracking—making your job much harder. So it's especially
important to crack smaller sections. Cut the mesh with
a bolt cutter as you work. Watch out for the sharp wire
spikes left sticking out of the concrete chunks. If the
concrete contains rebar, cut it with a reciprocating saw
and metal blade or an angle grinder and metal cutoff
wheel.

Get a heavy-duty hauler

Power wheelbarrow

A rented power wheelbarrow makes rubble removal a breeze—especially if you can find
someone else to do the loading.

For most jobs, a heavy-duty wheelbarrow
is the best hauler for rubble.
Don't use a light-duty model—it
won't survive the day. And don’t
haul big loads or you won't survive
the day. Ten full loads will wear you
out faster than 20 half loads. If the
path to the trash container is uphill,
consider renting a power wheelbarrow.